3x^2-12x+21=47

Simple and best practice solution for 3x^2-12x+21=47 equation. Check how easy it is, and learn it for the future. Our solution is simple, and easy to understand, so don`t hesitate to use it as a solution of your homework.

If it's not what You are looking for type in the equation solver your own equation and let us solve it.

Solution for 3x^2-12x+21=47 equation:


Simplifying
3x2 + -12x + 21 = 47

Reorder the terms:
21 + -12x + 3x2 = 47

Solving
21 + -12x + 3x2 = 47

Solving for variable 'x'.

Reorder the terms:
21 + -47 + -12x + 3x2 = 47 + -47

Combine like terms: 21 + -47 = -26
-26 + -12x + 3x2 = 47 + -47

Combine like terms: 47 + -47 = 0
-26 + -12x + 3x2 = 0

Begin completing the square.  Divide all terms by
3 the coefficient of the squared term: 

Divide each side by '3'.
-8.666666667 + -4x + x2 = 0

Move the constant term to the right:

Add '8.666666667' to each side of the equation.
-8.666666667 + -4x + 8.666666667 + x2 = 0 + 8.666666667

Reorder the terms:
-8.666666667 + 8.666666667 + -4x + x2 = 0 + 8.666666667

Combine like terms: -8.666666667 + 8.666666667 = 0.000000000
0.000000000 + -4x + x2 = 0 + 8.666666667
-4x + x2 = 0 + 8.666666667

Combine like terms: 0 + 8.666666667 = 8.666666667
-4x + x2 = 8.666666667

The x term is -4x.  Take half its coefficient (-2).
Square it (4) and add it to both sides.

Add '4' to each side of the equation.
-4x + 4 + x2 = 8.666666667 + 4

Reorder the terms:
4 + -4x + x2 = 8.666666667 + 4

Combine like terms: 8.666666667 + 4 = 12.666666667
4 + -4x + x2 = 12.666666667

Factor a perfect square on the left side:
(x + -2)(x + -2) = 12.666666667

Calculate the square root of the right side: 3.559026084

Break this problem into two subproblems by setting 
(x + -2) equal to 3.559026084 and -3.559026084.

Subproblem 1

x + -2 = 3.559026084 Simplifying x + -2 = 3.559026084 Reorder the terms: -2 + x = 3.559026084 Solving -2 + x = 3.559026084 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '2' to each side of the equation. -2 + 2 + x = 3.559026084 + 2 Combine like terms: -2 + 2 = 0 0 + x = 3.559026084 + 2 x = 3.559026084 + 2 Combine like terms: 3.559026084 + 2 = 5.559026084 x = 5.559026084 Simplifying x = 5.559026084

Subproblem 2

x + -2 = -3.559026084 Simplifying x + -2 = -3.559026084 Reorder the terms: -2 + x = -3.559026084 Solving -2 + x = -3.559026084 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '2' to each side of the equation. -2 + 2 + x = -3.559026084 + 2 Combine like terms: -2 + 2 = 0 0 + x = -3.559026084 + 2 x = -3.559026084 + 2 Combine like terms: -3.559026084 + 2 = -1.559026084 x = -1.559026084 Simplifying x = -1.559026084

Solution

The solution to the problem is based on the solutions from the subproblems. x = {5.559026084, -1.559026084}

See similar equations:

| 3x^2-12x+21=y | | ln(x-3)=ln(2x^2-4)-lnx | | 12=2m/3-4 | | X*16=10 | | 60=x/720000 | | 15x-8=1+9x | | 70=x/525000 | | 60=x/660000 | | x(3x-2y+7)= | | x^2-6x+8=6 | | 60=x/450000 | | 6x^2-18xy=0 | | 70=x/300000 | | x^3-17x+3=0 | | x/3-4=0 | | x^3-17x+1=0 | | x^4+4y^3-16x=0 | | z^3=i | | 60=x/600000 | | (X-4+4i)(x-4-4i)=0 | | (1-p^2)xy+p(x^2-y^2)=0 | | 2/x=4/8 | | x=0.6x+24 | | 3x-8+5x=1+2x+9 | | 14x-3y-4z=3 | | 8x-7+5z=30 | | 2x-5=4+x | | ((x^2-1)*12)=1 | | z=14z+1 | | (x^2-1*12)=1 | | 6x+2y-z=7 | | 5a^3-a^5=11 |

Equations solver categories